The present invention relates to a method for selecting any one of the heads of a cassette tape recorder of the automatic reverse type, and a head selection mechanism for its practice.
In a cassette tape recorder of the automatic reverse type, a plurality of magnetic heads on a head lever, for example, a pair of magnetic heads, are each alternately brought to a position in which the head comes in contact with a magnetic tape by means of a pivotal movement of the head lever. The fast forward (FF), rewind (REW) and cassette eject modes are obtained by setting the head lever in a neutral position, that is, a position in which the magnetic heads do not come in contact with the magnetic tape. In the FF, REW and cassette eject modes, a pinch roller supported on a pinch roller lever is spaced apart from the magnetic tape. In a conventional cassette tape recorder of the automatic reverse type, a selection lever is incorporated to move the pinch roller lever and the head lever to the neutral position in which the pinch roller of the pinch roller lever and the head of the head lever are not in contact with the magnetic tape. The selection lever is manually pivoted, so as to come in contact with the pinch roller lever which is forcibly moved with the head lever to the neutral position. In this manner, the known head selection mechanism comprises a selection lever which is manually operated. With this arrangement, a slide button or a push button is required for operating the selection lever. However, from the viewpoint of compactness and simplification of the cassette tape recorder, an electrically operated member such as a touch switch is desired in place of a mechanically operated member such as the slide button and the push button. Therefore, the known structure in which the selection lever is used does not satisfy the requirements for compactness and simplification of the cassette tape recorder.
A structure is known in which a pinch roller lever and a head lever are integrally formed, and the movement of this integral assembly is partially controlled by a solenoid. For example, in U.S. Pat. No. 3,716,242, a structure is described in which the movement of a head lever and a pinch roller from the neutral position to the position where the head lever and the pinch roller come in contact with a magnetic tape, is controlled by a solenoid. However, in the structure described above, the movement of the head lever and the pinch roller lever from the position in which the head and the pinch roller are in contact with the magnetic tape to the neutral position, is not controlled by the solenoid but by a selection lever operated when a manually operated member such as a push button is actuated. Therefore, the selection mechanism may not be entirely controlled by touch switches. A head selection method and a head selection mechanism for its practice have not been proposed, in which all the operations of the head lever and the pinch roller lever are performed by a single solenoid only.